Effects of Local CO_2 Enrichment on Strawberry Cultivation during the Winter Season

摘要

In strawberry production, carbon dioxide (CO_2) enrichment is widely used to promote crop photosynthesis and to improve growth and yield of strawberry fruits. However, a standard CO_2 enrichment method has not been established clearly. For sustainable strawberry production with high profitability, it is essential to establish an efficient system for CO_2 enrichment. Therefore, in this study, we newly propose a local CO_2 enrichment system. The system enriches CO_2 only ambient to strawberry crops, not a whole greenhouse, and thereby enables efficient control of CO_2 concentration. We applied this system in a strawberry cultivation greenhouse with ventilating windows and examined the performance of system. During the daytime on clear days with opened greenhouse ventilation windows, the proposed system stabilized the ambient CO_2 concentration to strawberry crops at 800 ppm. Furthermore, when the day after CO_2 enrichment was begun, strawberry crop photosynthesis and photosynthate translocation from source leaves were promoted as the effects of short-term CO_2 enrich-ment. Nevertheless, the yields and quality of fruits was not affected by the system. It is considered that long-term CO_2 en-richment thickened source leaves and thereby caused down-regulation of photosynthesis. Further consideration will be needed on effect of long-term CO_2 enrichment on physiological function of crops.